This section is intended to provide a background or context to the invention that is recited in the claims. The description herein may include concepts that could be pursued, but are not necessarily ones that have been previously conceived or pursued. Therefore, unless otherwise indicated herein, what is described in this section is not prior art to the description and claims in this application and is not admitted to be prior art by inclusion in this section.
The following abbreviations that may be found in the specification and/or the drawing figures are defined as follows:
AID association identifier
A/V audio/visual
Gbps giga-bits per second
GHz giga-hertz
HDMI high-definition multimedia interface
IANA internet assigned numbers authority
IETF internet engineering task force
IGMP internet group management protocol
IO input-output
LSB lest significant bits
MAC medium access control layer (layer 2)
PAL protocol adaptation layer (on top of layer 2)
PCP/AP private basic service set control point/access point
PIM protocol-independent multicast
WGA wireless gigabit alliance (also known as WiGig)
The WGA group seeks to create a global standard for interoperable products operating in the 60 GHz range. It is hoped to unify the next generation of entertainment, computing and communications devices at speeds more than 10 times faster than today's wireless LANs. At this early stage of development, products based on the WGA specification are to be capable of at least 1 Gbps at a typical range of 10 meters, with some implementations anticipated at speeds exceeding 6 Gbps and at greater distances.
The 60 GHz band is seen to be complementary to both 2.4 and 5 GHz, and there is a large amount of unlicensed spectrum available at this band worldwide. The 60 GHz band can enable higher data rates because it has much more bandwidth available (7-9 GHz of spectrum) vs. 83.5 MHz in the 2.4 GHz band. Applications that require multi-gigabit per second speeds (like uncompressed video transmission) to operate will be able to run in 60 GHz.
The WGA A/V PAL working group is developing a protocol adaptation layer (PAL) for A/V interfaces such as HDMI (for uncompressed video and audio) and DisplayPort. The envisioned use cases include high speed networking, wireless display and wireless IO.
However, the A/V PAL has currently no method to address a single A/V stream to multiple destination devices simultaneously. Since the protocol stack for A/V PAL does not include an IP protocol stack, the IP networking methods for multicast group management (e.g., IGMP which is a IETF L3 protocol for managing IP multicast groups, PIM, etc.) cannot be readily used in a PAL multicast arrangement. But there are use cases that would benefit from group addressing functionality, such as for example A/V streaming to multiple display devices in a conference room, or to multiple loudspeakers in an entertainment environment.
Attached as Exhibit A to the priority document U.S. provisional patent application 60/277,485 is a proposal for WGA by the Intel Corporation (Doc # PWG-2009-00yy-00-PAL-multicast-group-management, dated Sep. 3, 2009) by which a source device may create a multicast group, choose a multicast address, and invite destination devices to join that group by sending PAL connection setup request messages in which the multicast group is identified. In this proposal the source must know the prospective destination addresses in advance; it is based on inviting destination devices to join the multicast group.
Other references that may be of interest include IEEE 802.11v multicast which is an IP based multicast technique, and co-owned EP Patent Publication EP1619832 (published Jan. 25, 2006 and entitled “Multicast and Broadcast Data Transmission in a Short-Range Wireless Communication Network”; also published as US Patent Publication US 2006/0018319).